Envelopes having gummed flaps formed with tape



March 1962 E. J. D. STRATTON ETAL 3,026,018

ENVELOPES HAVING GUMMED FLAPS FORMED WITH TAPE Original Filed April 5, 1956' 3 Sheets-Sheet 1 w M Q a 1 Z; m fi W ,M w W Zone/a 5 =A March 20, 1962 E. .1. D. STRATTON ETAL 3,026,018

ENVELOPES HAVING GUMMED FLAPS FORMED WITH TAPE Original Filed April 5, 1956 5 Sheets-Sheet 2 March 1962 E J. D. STRATTON ETAL 3,026,018

ENVELOPES HAVING GUMMED FLAPS FORMED WITH TAPE Original Filed April 5, 1956 3 Sheets-Sheet 8 nite States Patent 3,026,018 ENVELOPES HAVING GUNHVIED FLAPS FORMED WITH TAPE Edwin J. D. Stratton, Glastonbury, Conn., and Donald J. Steidinger, Cicero, 11]., assignors to Uarco, Incorporated, a corporation of Illinois Original application Apr. 5, 1956, Ser. No. 576,478, now Patent No. 2,988,969, dated June 20, 1961. Divided and this application Aug. 13, 1959, Ser. No. 833,554

Claims. (Cl. 229-69) This invention relates to an assembly of series-connected envelopes, and more particularly to a method of applying adhesive to the closure flaps of such an assembly.

This is a divisional application of our application, Serial No. 576,478 filed April 5, 1956, now Patent No. 2,988,969, granted June 20, 1961, entitled Continuous Form Envelopes With Gummed Flaps and Method of Making Same, which is now pending in the Patent Oilice.

The primary object of the present invention is to provide a new and improved method of applying adhesive to the closure flaps of envelopes in continuous strip form. Heretofore, glue in a fluid state was deposited upon the closure flaps which necessitated a drying operation before the envelope strips were completed and ready for packaging and shipment. The present method eliminates this time-consuming operation, and it simplifies and facilitates the formation of series-connected envelopes with sealing flaps.

Another object is to provide an improved method of forming top flap envelopes in continuous strip form.

A further object is to provide an improved method of forming an assembly of series-connected envelopes having sealing adhesive on their closure flaps.

Another object is to provide an envelope which has a closure flap having a strip of gummed tape heat-sealed thereon.

Still another object is to provide an envelope having a strip of gummed tape which conforms precisely to the contour of the envelope flap so that the gummed adhesive is uniformly distributed transversely of the edge of the envelope flap.

The preferred embodiment and the preferred method of the present invention are illustrated in the accompanying drawings, in which:

FIG. 1 is a diagrammatic perspective View illustrating the steps in the preferred method of forming an assembly of series-connected envelopes;

FIG. 2, a plan view of an envelope of the assembly showing its front portion;

FIG. 3, a plan view of the envelope of the assembly showing its back portion;

FIG. 4-, a sectional view taken as indicated on line 44 of FIG. 3;

FIG. 5, a fragmentary plan view of the webs of envelope sheet material in juxtaposition showing the method steps in the formation of the envelope assembly;

FIG. 6, a plan view taken from the underside of FIG. 5;

FIG. 7, a diagrammatic perspective view illustrating the steps in the method of forming an assembly of sideflap, series-connected envelopes;

FIG. 8, a fragmentary plan view of a portion of the assembly of side-flap, series-connected envelopes;

FIG. 9, a plan view of a single, side-flap envelope; and

FIG. a sectional view taken as indicated on line 1tl10 of FIG. 9. i

The assembly of envelopes formed by the method of the present invention is frequently used in modern automatic business machines, such as typewriters and addressographs, where it is desired to imprint addresses quickly and accurately upon a series of envelopes. Such envelopes in continuous strip form are economical, and their ice use results in great savings of time and labor, because the strip may be continuously fed through the business machine.

One of the embodiments and methods is illustrated by the diagrammatic view in FIG. 1 of an assembly of top flap envelopes in continuous form. In this assembly, a sealing adhesive is applied to the envelope flaps as the individual evelopes are being formed from a pair of juxtaposed webs of envelope sheet material. The webs are joined at appropriate places to form a series of alternately spaced, transversely extending envelope pockets 13 and envelope flaps 14, as best seen in FIGS. 4 and 6. It is contemplated by the present invention that the assembly of envelopes may be formed in some other manner, and that an adhesive be later applied to the closure flaps in accordance with the present disclosure. 9

The diagrammatic view in FIG. 1 illustrates the preferred method of forming the assembly of series-connected, top-flap envelopes. A pair of webs, generally designated 15 and 16, of envelope sheet material are unwound from ordinary roll stock and superposed one on the other. One of the webs may have an entire face coated with a heat-sealing adhesive, or it may have bands of heat-sealing adhesive (sometimes simply called hot melt material) placed upon it by the location hot melt method, so that when the two webs are subjected to heat and pressure in appropriate places, they will be secured to-' gether to form the envelope pockets '13.

In FIG. 1, the heat-sealing adhesive has been applied to the lower face of the web 15 by the location hot-melt method. It. is preferred that the heat-sealing adhesive be placed so as to form a hot melt pattern including a pair of longitudinally extending bands 17 and 18, and a series of relatively wide, transversely extending bands 20 which are spaced longitudinally of the Web 15. The size and position of the bands, of course, may be varied in accordance with the type and size of envelopes which are to be formed.

Before the two webs are brought into juxtaposition, the web 16 is successively die-cut at longitudinally spaced points, and a series of die-cut slugs are removed so that a number of similar transversely extending die-cut portions or openings 21 are formed in the web 16. The die-cut portions 21 are preferably similar to each other and equidistantly spaced longitudinally of the web 16. After the die-cut slugs are removed, a pair of longitudinally extending marginal edge portions 22 and 23 remains at the sides of the web 16 which forms a ladderlike configuration in the web 16 before it is brought together with the web 15. The marginal edge portions at opposite ends of each of the die-cut portions 21 are left with suificient width so that the web 16 will still have considerable strength and resistance to tearing as it is advanced with the Web 15.

As the webs 15 and 16 are brought together, they are positioned with respect to each other so that a transversely extending segment of each of the transverse bands 20 is exposed at the forward edge of each of the die-cut portions 21, as best seen in FIG. 6. The marginal edge portions 22 and 23 are preferably positioned so as to cover each of the longitudinally extending side bands of adhesive 17 and 18. After the webs 15 and 16-have been correctly positioned against each other, they are advanced by a heatsealing station which applies heat and pressure to the regions above and below the transverse band 20 to form a bottom 24 in each successive pocket 13. As shown in FIG. 1, this heat-sealing station may include an upper heat-seal bar 25 extending transverselyof the webs 15 and 16, and positioned over a cooperating lower heatseal bar 26. v t

' In the preferred method, envelope flap adhesive is applied to each successive envelope flap 14 at the same time that the bottom of each envelope pocket is formed. To this end, a pair of feed rolls 27 and 28 are provided adjacent the heat-seal bars 25 and 26 to feed lengths of tape 30 from a supply roll -31 transversely of the advancing Webs 15 and 16. The tape is preferably provided with a moisture sensitive adhesive 32 on its exposed face, and may have a heat-seal adhesive 33 on its sealed or flapcontacti'n'g face.

Although it is contemplated by the invention that the webs may be continuously advanced, it is preferred that an intermittent drive be provided. Both the heat-seal bars 25 and 2 6 and the feed rolls 27 and 28 are operated in timed relation to the drive means advancing the webs 1S and 16. Each time that the webs 15 and 16 start their forward advance, the heat-seal bar 25 is in its upward inoperative position, and the feed rolls 27 and 2S advance a tape length 30 to a position on the top face of the lower heat-seal bar 26. The webs 15 and 16 are then brought to a halt so as to position one of the transverse bands 20 of heat-seal material between opposed faces of the bars 25 and 26. At this time the portion of the transverse band 21) which is exposed at the forward edge of each of the die-cut portions 21 is positioned above the length of tape 30 resting on the lower heat-seal bar 26.

The heat-seal bars 25 and 26 are then brought together, and heat and pressure is applied to the transverse band 20 of heat-seal adhesive to form the bottom 24 of the envelope pocket 13 and to adhere the length of tape 30 to the envelope flap 14. As the heat-sealing operation is performed, a cutting member 34, preferably operating in timed relation with the bars 25 and 26, severs the length of tape 30 from the supply roll 31.

At the same time that the bottom 24 of the envelope pocket 13 is being formed, additional heating elements maybe provided to close sides 35 and 36 of that envelope pocket. This sealing operation is preferably performed by two pairs of heat-seal bars 37, 38 and 40, 41, each pair of which is oppositely disposed above and below the side 1 bands of adhesive 17 and 18, respectively, in the marginal edge portions 22 and 23 of the envelope assembly, as best seenin FIG. 1. Preferably, the heat-seal bars 37, 38 .and 4t), 41 are spaced forwardly from the bars 25 and 26, one envelope length in the envelope assembly. All three pairs of heat-seal bars, 25, 2 6, 37, 38 and 40, 41, operate together and in timed relation to the intermittent advancement of the envelope assembly. Thus the continuous envelope assembly is advanced a predetermined distance,-depending upon the size of the envelope being formed; the assembly is then stopped, and the cooperating heat+sea1 bars are pressed together toseal appropriate portions of the advancing Webs, and successively form pockets 13. Each pair of cooperating heat-seal bars is then moved apart, and the intermittent drive advances the envelope assembly another envelope length so that the process can again be repeated.

It is next preferred that the opposite ends of the envelope flaps 14 be die-cut as at 42 and 43 to give the desired shape to each flap. As best seen in FIG. 6, the diecutting operation preferably produces a triangular opening and removes end portions of the flap 14 and tape 30 and small inner segments from the marginal edge portions 22 and 23. The die-cut areas are preferably located so that a pair of projections 44 and 45 remain in the marginal edge portions 22 and 23 and extend across a line of fold 46 which is later impressed in each envelope of the assembly. In the completed envelope, as illustrated in FIGS. 2, 3 and 4, the projections 44 and 45 strengthen each individual envelope at the extremities of its line of fold 46. In addition, the gummed tape 30 is positioned on each envelope flap 14 so as to conform precisely to the contour of that flap and to uniformly distribute moisturesensitive adhesive completely across the free edge of each of the flaps.

The ladder-like web 16 is most apt to be turned or broken prior to the time that it is joined to the web 15. The web 16 generally tears at 22a or 23a in its marginal edge portions 22 and 23 at opposite ends of the die-cut portion 21. For this reason it is desirable to maintain these marginal edge portions at 2211 and 230 as wide as possible to lend added strength to the Web 16. The present method is particularly wellradapted to assure this important feature since the die-cuts at 42 and 43 later remove inner segments of the edge portions 22 and 23 and form projections 44 and 45 in each envelope of the completed assembly. It should also be noted that by retaining the width of Web 16 at 22a and 23 1 during heat-sealing operations, the bands 17 and 18 of heat-seal adhesive are completely covered, and the lower heat-seal bar 25 cannot adhere to the advancing Webs of sheet material and cause them to break or tear.

The marginal edge portions 22 and 23 are next preferably trimmed as indicated at 47 and 48, and each marginal edge portion is provided with a series of equally spaced apertures 50 which form a feed track so that the ,completed envelope assembly can be conveniently advanced by the pinwheel feed of a writing machine.

' Suitable means are then provided for detaching the marginal edge portions of the envelope assembly from the successively connected envelopes, and suitable means are also provided for detachably connecting each envelope from the envelopes adjacent it. As herein shown, lines of weakening 51 and 52 are provided to separate the envelope assembly from each of the marginal edge portions 22 and 23, and lines of weakening 53 are provided between each of the envelope flaps 14 and each bottom 24 of the next adjacent envelope so that they may be conveniently separated when desired.

FIG. 7 is a diagrammatic illustration of the method of applying gummed tape to the closure 'flaps of an assent bly of series-connected, side-flap envelopes. An upper web 54 of envelope sheet material is preferably provided with an appropriate pattern of heat-sealing adhesive by the location hot-melt printing method. As herein shown, a series of equally spaced transversely extending bands of adhesive 55 may be applied to the .underface of the upper web 54 and be joined at one end to a longitudinally extending band of heat-sealing adhesive 56, as best seen in FIG. 7. A second longitudinally extending band of heat-sealing adhesive 57 is preferably provided in a marginal edge portion 58 of the upper web 54, and is spaced from each of the adjacent ends of the transverse bands 55.

A lower web 60, which is slightly narrower than the upper web 54, is next brought into juxtaposition with the upper web 54 so that the marginal edge portions adjacent the longitudinal band 56 are substantially in alignment. Thus, the marginal edge portion 58 projects outwardly beyond a marginal edge 61 of the lower web 60.

The two webs in juxtaposition are then advanced between a pair of opposed cooperating heat-seal bars 62 and 63. The webs may either be intermittently advanced or continuously advanced, but as herein shown, it is preferred that their advance be intermittent. The heat-seal bars 62 and 63 operate in timed relation to the intermittent advance of the two webs 54 and 60. When the bars 62 and 63 are pressed together, a sealing pattern is effected which closes a bottom edge 64 of a side-flap envelope, generally designated 65, and a pair of side edges 66 and 67 of an adjacent pair of side-flap envelopes 65. When the next envelope is advanced beneath the bars 62 and 63, its bottom and its remaining side edge is sealed, and in addition, a side edge of the envelope next to be ad vanced beneath the bars has one of its side edges sealed.

A pair of feed rolls 68 and 70 are diagrammatically illustrated in FIG. 7, and these wheels are driven in timed relation to the intermittent advance of the assembly of envelopes. The end of a supply roll 71 of gummed tape 69, similar to the gummed tape described above, is threaded through the feed rolls 68 and 7t} and deposited in a continuous strip upon the longitudinal band of heatsealing adhesive 57 on the marginal edge portions 58. The gummed tape is intermittently fed to a position between a pair of opposed heat-seal bars 72 and 73 which, by heat and pressure, activates the adhesive in the longitudinal band 57 so as to adhere the gummed tape to the marginal edge 58 of the assembly. The marginal edge portions 58 and the opposite joined marginal edge portions may then be trimmed at 74, as described above, and a series of equally spaced apertures 75 may be provided in the marginal edges of the assembly to form a feed-track for conveniently advancing the assembly through the pinwheel feed of a writing machine.

The marginal edge portion 53 may then be die-cut, as at 76, to form successive side flaps 77 for each envelope in the assembly. Suitable means are also provided in the form of lines of weakening 78, 3t) and 81 to permit detachment of the feed-tracks and to permit the individual envelopes to be separated from each other when desired. FIGS. 9 and 10 illustrate the side-flap envelope as it appears after separation from the assembly. Here again, the gummed tape 69 is positioned to conform precisely to the contour of the side flap of the envelope pocket so as to uniformly distribute moisture-sensitive adhesive across the free edge of the envelope flap.

The strip of series-connected, side fiap envelopes is then ready to be placed in the desired automatic business machine, and the successive envelopes may be addressed by merely advancing the strip through the machine.

The foregoing detailed description has been given for clearness of understanding only and no unnecessary limitations should be understood therefrom, for some modifications will be obvious to those skilled in the art.

We claim:

1. An assembly of series-connected envelopes for use in a writing machine, comprising: a plurality of envelopes formed in a continuous strip, each envelope having a flap, a front and a back, each front and back having adjacent marginal and bottom edges appropriately adhered together to form an envelope pocket having an opening extending transversely of the assembly, and each flap having its free end detachably secured to the closed bottom edge of the envelope pocket of an adjacent envelope to form said continuous strip of envelopes; a transverse line of fold formed between the envelope pocket opening and the flap of each of said envelopes in said continuous strip; a longitudinally extending feed band detachably secured to each of the series of marginal edges of the envelopes in the continuous strip; and longitudinally projecting portions on each of said backs adjacent to and spaced inwardly from each of the feed bands, each of said projecting portions extending across an end of each line of fold and being adhered to its respective flap to strengthen each of the envelopes in the opposite ends of its line of fold.

2. An assembly of series-connected envelopes as specified in claim 1, in which a length of tape is secured to each flap, each of said lengths extending transversely of the continuous strip of envelopes and having a moisturesensitive adhesive on its exposed face, and a heat-sensitive adhesive on its concealed face, said heat-sensitive adhesive adhering each of the lengths of tape to its respective flap.

3. An envelope comprising: a front and a back appropriately joined at their peripheral edges to form an envelope pocket; a flap hinged to said front along a line of fold, said flap being swingable about said line of fold to close said envelope pocket; and longitudinally projecting portions formed integrally with the back and positioned at the opposite ends of said line of fold, said longitudinally projecting portions extending across the line of fold between the front and the flap and being adhered to the flap so as to strengthen the envelope in the opposite ends of its line of fold.

4. An envelope as specified in claim 3 in which a length of tape is adhered transversely of the free end of the flap and has an edge portion substantially conforming throughout its length to the contour of the edge of said free end of the flap, said tape being provided with a substantially uniform film of moisture-sensitive adhesive upon its exposed face whereby said flap may be sealed to the back to close the envelope pocket.

5. An envelope assembly as specified in claim 4 in which heat-seal material is interposed between the length of tape and the flap to adhere the tape to the flap.

References Cited in the file of this patent UNITED STATES PATENTS 179,351 Rogers June 27, 1876 1,336,092 Schenkel-berger Apr. 6, 1920 2,342,702 Sherman Feb. 29, 1944 2,372,008 Krueger Mar. 20, 1945 2,722,369 Reuter Nov. 1, 1955 2,824,685 Patton Feb. 25, 1958 2,895,534 Steidinger July 21, 1959 

